Materials capable of binding specific cells or molecules, especially macromolecules such as proteins, peptides and nucleic acids, play an important role in a wide range of biomedical applications that include molecular separation, biosensors, and medical devices.
For example, affinity chromatography exploits the recognition between an immobilized ligand and the protein to be separated. In biospecific affinity chromatography, monoclonal antibodies or enzyme substrates are covalently linked to an inert matrix to purify the proteins recognized by the antibodies, or the enzymes that bind to the substrates. Biomolecules are, however, labile and expensive, and often difficult to immobilize.
Biosensors combine a biological recognition mechanism with a physical transduction technique. They find various applications in medical diagnostics (in vitro and in vivo), environmental monitoring, and industrial processing. A biosensor usually utilizes biomolecules, such as antibodies or receptors, or biological systems, such as cells, as sensing elements for analytes. Again, the development of biosensors is largely impeded by problems with biological components, such as their inherent instability.
The clinical success of a medical prosthesis, that is inserted into a mammalian body, depends primarily on the ability of the surface of the prosthesis to promote or inhibit specific protein and cellular responses. When a medical prosthesis is placed into the body, proteins adsorb almost instantaneously onto the surface. The cellular responses of the body to the prosthesis are mediated by interactions between the adsorbed protein layer on the prosthesis surface and the protein receptors on cell surfaces. Thus, the composition and conformation of the adsorbed protein layer on the surface of a prosthesis is largely responsible for dictating the biological response to that surface. To avoid rejection of the implanted biomaterial, therefore, a precisely engineered surface with ordered recognition sites for specific proteins is required. Despite many attempts to produce materials that preferentially bind a specific protein from plasma, most existing biomaterials exhibit a nonspecific biological reaction, with a broad spectrum of active processes simultaneously occurring, which may lead to rejection of the implant. A new generation of biomaterials engineered for specific protein recognition is required.
Thus, there is a need for structures, such as medical prostheses and biosensors, having surfaces that are durable and are capable of specifically binding cells or molecules, particularly biological macromolecules such as proteins, peptides and nucleic acids. Further, there is a need for methods of making structures having surfaces that are capable of specifically binding cells or molecules, especially biological macromolecules.